RDMA/core: Allow the ioctl layer to abort a fully created uobject

While creating a uobject every create reaches a point where the uobject is
fully initialized. For ioctls that go on to copy_to_user this means they
need to open code the destruction of a fully created uobject - ie the
RDMA_REMOVE_DESTROY sort of flow.

Open coding this creates bugs, eg the CQ does not properly flush the
events list when it does its error unwind.

Provide a uverbs_finalize_uobj_create() function which indicates that the
uobject is fully initialized and that abort should call to destroy_hw to
destroy the uobj->object and related.

Methods can call this function if they go on to have error cases after
setting uobj->object. Once done those error cases can simply do return,
without an error unwind.

Link: https://lore.kernel.org/r/20200519072711.257271-2-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

6 files changed, 48 insertions, 25 deletions

diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index bf8e149d3191..de3858515275 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -130,6 +130,17 @@ static int uverbs_destroy_uobject(struct ib_uobject *uobj,
 	lockdep_assert_held(&ufile->hw_destroy_rwsem);
 	assert_uverbs_usecnt(uobj, UVERBS_LOOKUP_WRITE);
 
+	if (reason == RDMA_REMOVE_ABORT_HWOBJ) {
+		reason = RDMA_REMOVE_ABORT;
+		ret = uobj->uapi_object->type_class->destroy_hw(uobj, reason,
+								attrs);
+		/*
+		 * Drivers are not permitted to ignore RDMA_REMOVE_ABORT, see
+		 * ib_is_destroy_retryable, cleanup_retryable == false here.
+		 */
+		WARN_ON(ret);
+	}
+
 	if (reason == RDMA_REMOVE_ABORT) {
 		WARN_ON(!list_empty(&uobj->list));
 		WARN_ON(!uobj->context);
@@ -647,11 +658,15 @@ void rdma_alloc_commit_uobject(struct ib_uobject *uobj,
  * object and anything else connected to uobj before calling this.
  */
 void rdma_alloc_abort_uobject(struct ib_uobject *uobj,
-			      struct uverbs_attr_bundle *attrs)
+			      struct uverbs_attr_bundle *attrs,
+			      bool hw_obj_valid)
 {
 	struct ib_uverbs_file *ufile = uobj->ufile;
 
-	uverbs_destroy_uobject(uobj, RDMA_REMOVE_ABORT, attrs);
+	uverbs_destroy_uobject(uobj,
+			       hw_obj_valid ? RDMA_REMOVE_ABORT_HWOBJ :
+					      RDMA_REMOVE_ABORT,
+			       attrs);
 
 	/* Matches the down_read in rdma_alloc_begin_uobject */
 	up_read(&ufile->hw_destroy_rwsem);
@@ -921,8 +936,8 @@ uverbs_get_uobject_from_file(u16 object_id, enum uverbs_obj_access access,
 }
 
 void uverbs_finalize_object(struct ib_uobject *uobj,
-			    enum uverbs_obj_access access, bool commit,
-			    struct uverbs_attr_bundle *attrs)
+			    enum uverbs_obj_access access, bool hw_obj_valid,
+			    bool commit, struct uverbs_attr_bundle *attrs)
 {
 	/*
 	 * refcounts should be handled at the object level and not at the
@@ -945,7 +960,7 @@ void uverbs_finalize_object(struct ib_uobject *uobj,
 		if (commit)
 			rdma_alloc_commit_uobject(uobj, attrs);
 		else
-			rdma_alloc_abort_uobject(uobj, attrs);
+			rdma_alloc_abort_uobject(uobj, attrs, hw_obj_valid);
 		break;
 	default:
 		WARN_ON(true);
diff --git a/drivers/infiniband/core/rdma_core.h b/drivers/infiniband/core/rdma_core.h
index 33978e0f1262..2b529233e159 100644
--- a/drivers/infiniband/core/rdma_core.h
+++ b/drivers/infiniband/core/rdma_core.h
@@ -64,8 +64,8 @@ uverbs_get_uobject_from_file(u16 object_id, enum uverbs_obj_access access,
 			     s64 id, struct uverbs_attr_bundle *attrs);
 
 void uverbs_finalize_object(struct ib_uobject *uobj,
-			    enum uverbs_obj_access access, bool commit,
-			    struct uverbs_attr_bundle *attrs);
+			    enum uverbs_obj_access access, bool hw_obj_valid,
+			    bool commit, struct uverbs_attr_bundle *attrs);
 
 int uverbs_output_written(const struct uverbs_attr_bundle *bundle, size_t idx);
 
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index d5642bcf93ee..86c97221872d 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -311,7 +311,7 @@ static int ib_uverbs_get_context(struct uverbs_attr_bundle *attrs)
 	return 0;
 
 err_uobj:
-	rdma_alloc_abort_uobject(uobj, attrs);
+	rdma_alloc_abort_uobject(uobj, attrs, false);
 err_ucontext:
 	kfree(attrs->context);
 	attrs->context = NULL;
diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
index 538affbc517e..42c5696f03bd 100644
--- a/drivers/infiniband/core/uverbs_ioctl.c
+++ b/drivers/infiniband/core/uverbs_ioctl.c
@@ -58,6 +58,7 @@ struct bundle_priv {
 
 	DECLARE_BITMAP(uobj_finalize, UVERBS_API_ATTR_BKEY_LEN);
 	DECLARE_BITMAP(spec_finalize, UVERBS_API_ATTR_BKEY_LEN);
+	DECLARE_BITMAP(uobj_hw_obj_valid, UVERBS_API_ATTR_BKEY_LEN);
 
 	/*
 	 * Must be last. bundle ends in a flex array which overlaps
@@ -230,7 +231,8 @@ static void uverbs_free_idrs_array(const struct uverbs_api_attr *attr_uapi,
 
 	for (i = 0; i != attr->len; i++)
 		uverbs_finalize_object(attr->uobjects[i],
-				       spec->u2.objs_arr.access, commit, attrs);
+				       spec->u2.objs_arr.access, false, commit,
+				       attrs);
 }
 
 static int uverbs_process_attr(struct bundle_priv *pbundle,
@@ -502,7 +504,9 @@ static void bundle_destroy(struct bundle_priv *pbundle, bool commit)
 
 		uverbs_finalize_object(
 			attr->obj_attr.uobject,
-			attr->obj_attr.attr_elm->spec.u.obj.access, commit,
+			attr->obj_attr.attr_elm->spec.u.obj.access,
+			test_bit(i, pbundle->uobj_hw_obj_valid),
+			commit,
 			&pbundle->bundle);
 	}
 
@@ -590,6 +594,8 @@ static int ib_uverbs_cmd_verbs(struct ib_uverbs_file *ufile,
 	       sizeof(pbundle->bundle.attr_present));
 	memset(pbundle->uobj_finalize, 0, sizeof(pbundle->uobj_finalize));
 	memset(pbundle->spec_finalize, 0, sizeof(pbundle->spec_finalize));
+	memset(pbundle->uobj_hw_obj_valid, 0,
+	       sizeof(pbundle->uobj_hw_obj_valid));
 
 	ret = ib_uverbs_run_method(pbundle, hdr->num_attrs);
 	bundle_destroy(pbundle, ret == 0);
@@ -784,3 +790,15 @@ int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
 	}
 	return uverbs_copy_to(bundle, idx, from, size);
 }
+
+/* Once called an abort will call through to the type's destroy_hw() */
+void uverbs_finalize_uobj_create(const struct uverbs_attr_bundle *bundle,
+				 u16 idx)
+{
+	struct bundle_priv *pbundle =
+		container_of(bundle, struct bundle_priv, bundle);
+
+	__set_bit(uapi_bkey_attr(uapi_key_attr(idx)),
+		  pbundle->uobj_hw_obj_valid);
+}
+EXPORT_SYMBOL(uverbs_finalize_uobj_create);
diff --git a/drivers/infiniband/core/uverbs_std_types_cq.c b/drivers/infiniband/core/uverbs_std_types_cq.c
index da4110a0eea2..73fbbeb2586c 100644
--- a/drivers/infiniband/core/uverbs_std_types_cq.c
+++ b/drivers/infiniband/core/uverbs_std_types_cq.c
@@ -129,16 +129,12 @@ static int UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE)(
 	obj->uevent.uobject.object = cq;
 	obj->uevent.uobject.user_handle = user_handle;
 	rdma_restrack_uadd(&cq->res);
+	uverbs_finalize_uobj_create(attrs, UVERBS_ATTR_CREATE_CQ_HANDLE);
 
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_CREATE_CQ_RESP_CQE, &cq->cqe,
 			     sizeof(cq->cqe));
-	if (ret)
-		goto err_cq;
+	return ret;
 
-	return 0;
-err_cq:
-	ib_destroy_cq_user(cq, uverbs_get_cleared_udata(attrs));
-	cq = NULL;
 err_free:
 	kfree(cq);
 err_event_file:
diff --git a/drivers/infiniband/core/uverbs_std_types_mr.c b/drivers/infiniband/core/uverbs_std_types_mr.c
index c1286a52dc84..a2722ef8496e 100644
--- a/drivers/infiniband/core/uverbs_std_types_mr.c
+++ b/drivers/infiniband/core/uverbs_std_types_mr.c
@@ -136,21 +136,15 @@ static int UVERBS_HANDLER(UVERBS_METHOD_DM_MR_REG)(
 
 	uobj->object = mr;
 
+	uverbs_finalize_uobj_create(attrs, UVERBS_ATTR_REG_DM_MR_HANDLE);
+
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_REG_DM_MR_RESP_LKEY, &mr->lkey,
 			     sizeof(mr->lkey));
 	if (ret)
-		goto err_dereg;
+		return ret;
 
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_REG_DM_MR_RESP_RKEY,
 			     &mr->rkey, sizeof(mr->rkey));
-	if (ret)
-		goto err_dereg;
-
-	return 0;
-
-err_dereg:
-	ib_dereg_mr_user(mr, uverbs_get_cleared_udata(attrs));
-
 	return ret;
 }